December 10th, 2015 by Piper Smith
Divider Calipers or, “map dividers” are used to measure the distance between two points on a map. Each end of the device is placed upon one of the points in question and then the width of the caliper’s opening was measured directly against a linear scale drawn on the map. On nautical charts, the distance was sometimes measured on the latitude scale appearing on the sides of the map: one minute of arc of latitude measuring approximately one nautical mile or 1852 meters.
Along with charts, this tool was an essential part of a captain’s navigational equipment and it is unlikely he would have simply forgotten it, but was instead forced to leave this and other tools of his trade behind in his haste to bring his crew and passengers to safety.